The following are the principal dyestuffs with the colours they produce. Several of the tints are very bright, but have now been superseded for convenience of usage by various mineral dyes. The Latin names are given where known and also the Scottish Gaelic names for various ingredients.
Many of the dyes are made from lichens, the useful ones for this purpose being known as crottle.
The process employed is to wash the thread thoroughly in urine long kept ("fual"), rinse and wash in pure water, then put into the boiling pot of dye which is kept boiling hot on the fire. The thread is lifted now and again on the end of a stick, and again plunged in until it is all thoroughly dyed. If blue, the thread is then washed in salt water, but any other colour uses fresh water.
Amateurs may wish to experiment with some of the suggestions, as urine (human or animal) is used in many recipes as a mordant. A number of the recipes used are for more than one colour, and this chart is only a guide.
Claret – "corcur" – the cudbearlichen, Lecanora tartarea, scraped off rocks and steeped in urine for three months, then taken out, made into cakes, and hung in bags to dry. When used these cakes are reduced to powder, and the colour fixed with alum.
White "cnotal" – Lecanora pallescens, "cnotal geal"
Rue – Galium verum, "ladies' bedstraw". A very fine red is obtained from this. Strip the bark off the roots, then boil them in water to extract the remainder of the virtue, then take the roots out and put the bark in, and boil that and the yarn together, adding alum to fix the colour.